186 NATUEAL CHANGES. 



margins of the lakes never remain the same for 

 half-a-century together. The streams bring down 

 soft soil incessantly ; and this more effectually 

 alters the currents than the slides of stones pre- 

 cipitated from the heights by an occasional storm. 

 By this deposit of soil new promontories are formed, 

 and the margin contracts, till many a reach of 

 waters is converted into land, inviting tillage. The 

 greenest levels of the smaller valleys may be seen 

 to have been once lakes : and no one who looks 

 down upon Grrasmere, for instance, from the hill- 

 field behind the Hollins, can have any doubt as to 

 what was once the extent of the waters. And, 

 while Nature is thus closing up in one direction, 

 she is opening in another. In some low-lying 

 spot a tree falls, which acts as a dam when the 

 next rains come. The detained waters sink, and 

 penetrate, and loosen the roots of other trees ; and 

 the moisture which they formerely absorbed goes 

 to swell the accumulation till the place becomes a 

 swamp. The drowned vegetation decays and sinks, 

 leaving more room, till the place becomes a pool 

 on whose bristling margin the snipe arrives to rock 

 on the bulrush, and the heron wades in the water- 

 lilies to feed on the fish which come there nobody 

 knows how. As the waters spread, they encounter 

 natural dams, behind which they grow clear and 

 deepen, till we have a tarn among the hills, which 

 attracts the browsing flock, and tempts the shep- 

 herd to build his hut near the brink. Then the 

 wild swans see the glittering expanse in their flight, 

 and drop down into it; and the waterfowl make 

 their nests among the reeds. This brings the 

 sportsman; and a path is trodden over the hills; 



